PHYSICAL REVIEW D, cilt.70, sa.5, 2004 (SCI-Expanded)
The constraints on the neutral gauge boson couplings, ZZgamma and Zgammagamma, are investigated at linear e(+)e(-) collider energies through the Zgamma production with longitudinal and transverse polarization states of the final Z boson. Because of high energy of linear electron-positron beams, initial state radiation (ISR) considerably changes the production cross section. We obtain an increase in the cross section by a factor of 2-3 due to ISR for transverse polarization and by a factor of 10-100 for longitudinal polarization states depending on the energy. We find the 95% C.L. limits on the CP conserving form factors h(3)(Z), h(4)(Z), h(3)(gamma), and h(4)(gamma) with integrated luminosity 500 fb(-1) and roots=0.5,1,1.5 TeV energies. It is shown that the longitudinal polarization of the Z boson, together with ISR, can improve sensitivities by factors 2-3.